78 lines
1.4 KiB
C++
78 lines
1.4 KiB
C++
/*
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*
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*/
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#include "iostream"
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#define Y_SIZE 3
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double* multiply( double ivec[], int N, double mtx[][Y_SIZE] );
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int main() {
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int Nx = 4;
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double ivec[Nx] = {1, 2, 50, 3.141517181920};
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double mtx[Nx][Y_SIZE] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}};
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// print vector
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std::cout << "Vector = ";
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std::cout << "[ ";
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for ( int i = 0; i < Nx; i++){
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std::cout << ivec[i] << ", " ;
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}
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std::cout << "]" << std::endl;
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// print matrix
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std::cout << "Matrix = ";
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std::cout << "[";
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for ( int i = 0; i < Nx; i++ ){
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std::cout << "[ ";
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for ( int j = 0; j < Y_SIZE; j++ ){
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std::cout << mtx[i][j] << ", " ;
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}
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std::cout << "]," << std::endl;
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}
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std::cout << "]" << std::endl;
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double * nvec = multiply( ivec, Nx, mtx );
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// print new vector
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std::cout << "Result = ";
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std::cout << "[ ";
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for ( int i = 0; i < Y_SIZE; i++){
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std::cout << nvec[i] << ", ";
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}
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std::cout << "]" << std::endl;
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delete nvec;
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// print the matrix as it is stored in memory
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std::cout << "In-Memory Matrix = ";
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std::cout << "[" << std::endl;
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for ( int i = 0; i < Nx*Y_SIZE; i++ ){
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std::cout << mtx[0][i] << ", ";
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}
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std::cout << std::endl;
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std::cout << "]" << std::endl;
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}
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double* multiply( double ivec[], int N, double mtx[][Y_SIZE] ){
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//allocate the new vector of length N
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double * nvec = new double[Y_SIZE];
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for ( int j = 0; j < Y_SIZE; j++ ){
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for ( int i = 0; i < N; i++ ){
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nvec[j] += ivec[i]*mtx[i][j];
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}
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}
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return nvec;
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}
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